Equipped with productive earplug active anti-noise transmitter-receiver factory and company, Fenghuo Hongsheng is one of the leading China wireless earbuds manufacturers and suppliers. Welcome to contact us. Earplug Active Anti-noise Transmitter-receiver adopts active anti-noise technology, and has the earplug receiver. So it can reduce the noise effectively and improve tone quality. The control box integrates the active anti-noise control switch, the transmitter, with the PTT key switch. This product has the features of nice anti-noise, comfortable and convenient wearing, etc.. It is the ideal audio terminal for portable communication equipment. Main Technical Specifications: Frequency response range: 20Hz～20000Hz; Receiving sensitivity: 115dB/mW; Receiving impedance: 32Ω (1000Hz) ; Noise reduction amount: broad band of voice controlled, Max.: 22dB(20Hz～3000Hz); Power supply: lithium battery (3.6V), with a charger.